The central goal of this project is to develop relevant transgenic mouse models of carcinogenesis elicited by human papillomavirus oncogenes, and to use those models to characterize and define the mechanisms underlying each stage in the development of HPV associated cancer. A set of transgenic mice has been produced in which expression of the human papillomavirus type 16 (HPV16) oncogenes is directed to the basal cells of the epidermis, resulting in the predictable development of progressive dysplasias in the external epidermis, and anal papillomas. These neoplastic lesions are analogous to those seen in infected humans, of which only a small fraction go on to develop cancer. A major focus of this project is to define the necessary genetic or epigenetic events for malignant conversion to carcinoma. It is our conviction that these events will prove of relevance to the mechanisms of PHV associated cancers in humans, and hence their identification and characterization are crucial both to understand the biology of the tumorigenesis process, and to set a foundation for design of rational therapeutic interventions. The specific aims of this proposal are to: characterize the various stages of HPV16 associated pathology in terms of abnormal cell proliferation, abrogation of orderly keratinocyte differentiation, and differential expression of the HPV16 oncoproteins; similarly analyze the anal papillomas and their preneoplastic stages; identify transgenic mouse lines showing HPV oncogene expression in cervix, and assess the pathological consequences and susceptibility to cervical carcinogenesis; derive keratinocyte cell cultures representing the stages in skin and anal/genital neoplastic development, and compare their cellular and biochemical properties; define the requirements for progression to carcinoma, assessing general genetic background, two specific candidate genes (TGFalpha and p53), environmental carcinogens, and immunodeficiency; elucidate the functions of the individual HPV oncogenes in neoplastic progression; and begin an investigation of cellular factors that contribute to carcinogenesis.